I found this in the Big Fish forum for this game; maybe this is your problem. Is it possible that you are trying to give the rose to the wrong person?
There are 2 singing guys; you are giving the rose to the wrong one. The right one is off the main square higher to the left. Once he has the rose (the actual Romero) more stuff will happen and you will be able to start playing through and have to do a lot more stuff.